Texas Instruments LM1117LD-2.5/NOPB

Overview

LM1117LD-2.5/NOPB from Texas Instruments is a fixed-output 2.5 V, 800 mA low-dropout linear regulator in SOT-223 package, featuring ±1% output voltage accuracy over 0°C to +125°C, 1.2 V dropout at 800 mA, and integrated thermal shutdown and current limiting. It delivers stable local regulation for microprocessor core supplies, industrial AC/DC front-ends, and ultrasound scanner power rails.

For engineers reviewing the LM1117LD-2.5/NOPB datasheet, LM1117LD-2.5/NOPB pinout, LM1117LD-2.5/NOPB application, or LM1117LD-2.5/NOPB equivalent, key selection criteria include dropout voltage at full load, thermal resistance in SOT-223 (61.6°C/W), output voltage tolerance across temperature, minimum required 10-µF tantalum output capacitor, and compatibility with fixed-output replacement paths such as TLV761.

Technical Context

The LM1117LD-2.5/NOPB implements a Zener-trimmed bandgap reference and NPN pass transistor architecture, enabling precise 2.5 V output regulation without external feedback components. Its internal current limit and thermal protection operate autonomously without external circuitry.

It requires no adjust pin connection-GND is internally tied to the ADJ terminal-and mandates a minimum 10-µF tantalum output capacitor for stability and transient response. Dropout voltage remains ≤1.3 V across the full 0°C to +125°C junction temperature range at 800 mA load.

Key Specifications

Pinout & Package

SOT-223 (DCY) package: 6.50 mm × 3.50 mm body, thermally enhanced tab (pin 2/TAB) for PCB heat sinking. Pin 1 = GND (ADJ/GND), Pin 3 = VIN, Pin 2 & TAB = VOUT.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout linear regulator applications.

Compared with LM1117LD-2.5/NOPB, TLV76125PDBVR offers higher current and lower dropout in a smaller package but demands new layout and thermal design, while TLV1117-25CDCYR provides identical functionality with extended temperature support-making it a drop-in upgrade for cold-environment applications.

Availability

LM1117LD-2.5/NOPB is available at Aetrix Electronics and suitable for industrial AC/DC power supplies, ultrasound scanner subsystems, and servo drive control modules requiring stable component supply with long-term lifecycle assurance.

Supply support for LM1117LD-2.5/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company specializing in analog, embedded processing, and power management ICs, with leadership in high-reliability linear regulators and precision voltage references.

The LM1117 product line delivers cost-optimized, thermally robust LDOs for industrial, medical, and infrastructure applications where simplicity, proven reliability, and wide-temperature operation are critical.

FAQ

What is the maximum input voltage rating for LM1117LD-2.5/NOPB?

The absolute maximum input voltage for LM1117LD-2.5/NOPB is 20 V, but the recommended operating maximum is 15 V. Exceeding 15 V risks accelerated degradation under sustained operation, especially at elevated temperatures. The device maintains regulation down to a minimum input of 3.9 V (2.5 V + 1.4 V headroom), and its 1.3 V max dropout ensures stable 2.5 V output across the full 0°C to +125°C junction temperature range. Always observe derating curves in the datasheet for thermal design.

Does LM1117LD-2.5/NOPB require an external capacitor on the ADJ pin?

No, LM1117LD-2.5/NOPB does not require an external capacitor on the ADJ pin because it is a fixed-output variant-its ADJ terminal is internally connected to GND. Only the adjustable version (LM1117-ADJ) uses the ADJ pin for external feedback. For LM1117LD-2.5/NOPB, a minimum 10-µF tantalum capacitor is required at the VOUT pin to ensure stability and transient response; ceramic alternatives must meet ESR requirements (0.3–22 Ω).

What thermal resistance values apply to LM1117LD-2.5/NOPB in SOT-223 package?

LM1117LD-2.5/NOPB in SOT-223 (DCY) package has RθJA = 61.6°C/W (junction-to-ambient, standard JEDEC 2S2P board), RθJB = 10.4°C/W (junction-to-board), and RθJC(top) = 42.5°C/W. These values assume proper PCB copper pour under the thermal tab (pin 2/TAB). For high-power operation (>500 mA), thermal vias to inner ground planes and ≥1 in² copper area are strongly recommended to approach the RθJB value and avoid thermal shutdown.

Can LM1117LD-2.5/NOPB be used as a direct replacement for LM1117-2.5 in existing designs?

Yes, LM1117LD-2.5/NOPB is functionally and pin-compatible with LM1117-2.5 in SOT-223 package, sharing identical electrical specifications, pinout, and thermal characteristics. Both deliver 2.5 V ±1%, 800 mA, and 1.2–1.3 V dropout. The "LD" suffix denotes tape-and-reel packaging per TI's ordering nomenclature, not a functional change. No PCB or schematic modifications are required when substituting LM1117LD-2.5/NOPB for LM1117-2.5.

What is the minimum output capacitance required for stable operation of LM1117LD-2.5/NOPB?

The minimum output capacitance for stable operation of LM1117LD-2.5/NOPB is 10 µF tantalum, with ESR between 0.3 Ω and 22 Ω. This value is specified in the datasheet for guaranteed phase margin and transient response. While larger capacitance improves load step recovery, reducing below 10 µF risks oscillation or poor regulation. Ceramic capacitors may be used only if their effective series resistance is intentionally increased (e.g., via series resistor) to fall within the specified ESR window.